where perpendicular bisectors intersect
We may use this applet to explore and explain the following property.
For a triangle ABC, if two of its perpendicular bisectors intersect at a point P, this point should also lie on the third perpendicular bisector.
You may try the following steps to explore the figure.
- Click the check box to show a movable point Q and the segments connecting it with A, B and C.
- What happens when Q lies on the perpendicular bisector of AB?
- What happens when Q lies on the perpendicular bisector of AC?
- What would you expect to see if Q is moved to P? Why?
Go ahead to move Q and check. Write down your observation here.
Whenever BQ=CQ, Q should lie on the perpendicular bisector of BC. (If needed, move Q to some possible positions and check.) Do you know why?
Explain why you are sure P is one of those points equally far away from B and C (that means BP=CP).
So, can you conclude that P must lie on the perpendicular bisector of BC?